I understand that ventilation is important, and I’ll move the UPS to sit on top of the server tower rather than beside it, but clearly the overheating here was not due to a hot room but to a battery or controller failure. The building where this unit is installed does not have air conditioning, but the high in San Diego that day was 71 F, so the room was well below 80 F (27 C). Here’s the event log, showing the “battery disconnected” event at 2:39pm:Īnd here’s the temperature graphed from 4:10am to 4:50pm:Īccording to its specs, the DLA1500 is supposed to operate safely in an environment up to 40 C. The temperature was 40 C when the unit reported “battery disconnected.” Is it a coincidence that 40 C is the temperature at which the fan turns on ( KB article)? Perhaps some safety switch was tripped to disconnect the battery? The fuse between the batteries did not trip. Reviewing the PowerChute data log, I see that the temperature is usually around 30 Celcius (86 Fahrenheit), but starting at about 7:30am, it slowly climbed to 41 C (106 F). I disconnected the two batteries from each other and left them outside overnight to cool. And get this: two hours after removing them, the batteries still felt hot! I guess I’m lucky I didn’t have flammable hydrogen gas escaping as this thread says can happen. I finally managed to hook a wrench around the top and pull them out. The plastic pull tab broke off when I tried to pull out the batteries. When I got the battery door open, I could see the batteries bulged somewhat and were very hot. Of greater concern was that the unit was almost too hot to touch.
For some reason there was no corresponding event in the PowerChute event log. Once I got on site, I found that the “Replace Battery” light was blinking.
Of course the battery is not disconnected the connection inside the unit is a very secure clip that can’t just wiggle loose. I got an email from APC PowerChute Business Edition that said simply “Battery Disconnected.” The connected UPS is an APC SmartUPS 1500 model DLA1500 (the Dell equivalent of an SUA1500).